The demand for fast and effective ways of retrieving relevant information is ongoing. Question-Answering systems which receive a question from a user by voice input or in other ways, and then return an answer (as opposed to a list of relevant Web pages or URLs) are increasingly used to retrieve facts and information. Search engines which receive text based queries also operate to return ranked lists of documents to users which are relevant to the query. Insight systems are available which operate in conjunction with other tasks, such as word processing or reading, which a user is engaged in and enable the user to quickly and simply retrieve facts and information which are relevant to the ongoing task. Many other types of information retrieval system are available, including those directed at enterprise workers or other communities of individuals where users are able to retrieve information from a knowledge system conceptually organized as a graph—with individuals, documents, and other entities as vertices, and the relations between them as arcs.